Organic ester compounds are good solvents used in quantities in synthetic resin industries, such as for paints, inks, adhesives and detergents. At present, ether compounds are mainly divided into two categories, i.e. E series and P series. The E series of ether compounds are obtained from the synthesis of alcohols and ethylene oxide while P series of ether compounds are obtained from the synthesis of alcohols and propylene oxide. For example, the P series of ether compounds obtained from the synthesis of methanol and propylene oxide will produce two isomers, one of which is 1-methoxy-2-propanol having the structural formula: ##STR5## and other is 2-methoxy-1-propanol having the structural formula: ##STR6## with a proportion of the former to the later in 98:2. The former is dominant and thus commonly referred as propylene glycol monomethyl ether.